Laundry wastewater or cleaning wastewater (hereinafter, representatively referred to as “laundry wastewater”) that is discharged from, for example, plant facilities may include, for example, trace amounts of radioactive substances, as well as organic materials such as detergents, cloth fibers, fats and carbohydrates. In a wastewater treatment, these substances must be eliminated and made innocuous in order to satisfy effluent standard values.
Regarding conventional treatment methods for making laundry wastewater innocuous, there has been suggested a laundry wastewater treatment device capable of effectively treating laundry wastewater from a plant facility, by which laundry wastewater discharged from a plant facility is introduced into a biological treatment tank, the laundry wastewater is aerated and mixed with activated sludge therein, and a mixed liquid thus obtained is subjected to solid-liquid separation using a precision filtration membrane (PTL 1).